162 



DEFINITE INFLORESCENCE. 



others being subsequently developed in a centrifugal order. In some of 

 the Pink tribe, as Dianthus barbatus, Carthusianorum, &c., in which 

 the peduncles are short, and the flowers closely approximated, with a 

 centrifugal expansion, the inflorescence has received the name of fascicle. 

 A similar inflorescence is seen in such plants as Xylophylla longifolia 

 (fig. 229). When the axes become very much shortened, the arrange- 

 ment is more complicated in appearance, and the nature of the inflores- 

 cence is indicated by the order of opening of the flowers. In Labiatas, 

 as in the Dead nettle (Lamium), the flowers are produced at the axil 

 of each of the leaves, and might be looked upon as ordinary whorls, 

 but on examination it is found that the central flower expands first, 

 and that the expansion is thus centrifugal. The inflorescence is there- 

 fore truly cymose, the flowers being sessile, or nearly so, and the clusters 

 are called verticillasters (verticilltis, a kind of screw). 



340. Sometimes the bract on one side of a dichotomous cyme, 

 especially towards the summit of the inflorescence, does not give 

 origin to buds, as seen in the upper flower of fig. 250. When a 

 single bract only is produced, in place of two, there is often an anoma- 

 lous cymose inflorescence produced, resembling a raceme. Thus, in 

 Alstromeria, as represented at fig. 251, the axis, ', ends in a flower, 

 which has been cut off, and a leaf. From the axil of this leaf, that is, 

 between it and the primary axis, ', a secondary axis, a", is formed, 

 ending in a flower/", and producing a leaf about 

 the middle. From the axil of this leaf, a tertiary 

 floral axis, a"', endingin aflower,/'", isdeveloped, 

 and so on. Sometimes the bract on the opposite 

 side shows itself, as at a. This inflorescence 

 therefore, although it appears simple and race- 

 mose is truly compound and cymose, consisting 

 of a series of separate axes, with a 

 centrifugal expansion. The flower- 

 ing branch often exhibits, in such 

 cases, a series of curvations. In cer- 

 tain orders of plants, especially 

 Boraginacea?, the bracts being alter- 

 nate, give rise to an inflorescence 

 of this kind. Thus, in fig. 252, a 

 is a primary axis, ending in a flower, producing another, ft, and that, 

 a third, c, a fourth, d, &c., ah 1 on the same side. In such a case there 

 is usually a remarkable curvature resembling the tail of a scorpion, 



Fig. 251.- -False raceme of a species of Alstromeria, a' a" a'" a"", Separate axes successively 

 developed, .vhich appear to form a simple continuous raceme, of which the axes form the inter- 

 nodes. It is a eompound determinate inflorescence, however, with centrifngal evolution. Each 

 of the axes is produced in the axil of a leaf, and is terminated by a flower,/'/"/'"/"", opposite 

 to that leaf. 



Fig. 252. Figure to show the formation of a scorpioidal or helicoid cyme, consisting of separate 

 axes, a b c d e. 



